import java.util.Arrays;

public class OnlyYou {
    public static void main(String[] args) {

        int[] a = { 45, 12, 67, 45, 98, 12, 34, 98, 67, 78, 34, 56, 56, 78, 10 };
        System.out.println(onlyYou(a));
    }

    public static int onlyYou(int[] a) {
        int back = 0;

        for (int i = 0; i < a.length; i++) {
            back ^= a[i];
        }

        return back;
    }
}
